3. MongoFDW SERVER CREATE

  • if you succeed the mongo_fdw extension, next step is creating ‘mongo_server’.
CREATE SERVER mongo_server FOREIGN DATA WRAPPER mongo_fdw
OPTIONS (address '127.0.0.1', port '27017');
  • mongo_server : server name. server name is possible customizing.
    • (e.g mongo_server -> m_server, test, test1, mongo, etc…)
  • mongo_fdw : extension name.
  • address : host address
    • if MongoDB is installed remote OS, 127.0.0.1 -> host address texting
  • port : host port
    • MongoDB default port is 27017. enter current port texting.

3-1. MongoFDW to AgensGraph(A.G) USER MAPPING

CREATE USER MAPPING FOR test SERVER mongo_server;
  • test : AgensGraph user(role) name.
  • if you don’t know user, in AgensGraph console, enter the ‘\du’ Alt text
  • mongo_server : mongoFDW SERVER name
  • MongoFDW SERVER is used AgensGraph user(role). need a user mapping.

3-2. Creating AgensGraph(A.G) Foreign Table for MongoDB

CREATE FOREIGN TABLE IF NOT EXISTS public.c_table1
( name TEXT )
SERVER mongo_server OPTIONS (database 'test', collection 'collection1');
  • public.c_table1 : foreign table name
  • name TEXT : foreign table column. MongoDB document data(JSON) key is table column. column type is TEXT
  • mongo_server : MongoFDW SERVER name.
  • ‘test’ : MongoDB name
  • ‘collection1’ : test MongoDB collection name

4. RESULT

Alt text

  • MongoDB data is three keys and three values
    • {name : test}, {name : test1}, {name:test2}
  • AgensGraph foreign table ‘SELECT’. It is possible to write with the SQL that you know (If there are two or more tables, JOIN is possible.) 
    SELECT * FROM public.c_table1;

** If you is created(modified) foreign table by SQL query, Avoid creating, modified. Foreign table is using only for SELECT purposes. if you modified, need to ‘foreign table to materialized view’